1. Field of the Invention
The invention relates to an electrically operated drive device adapted for driving a latch-actuating spindle of an electrically operable lock, more particularly to an electrically operated drive device that permits both manual and automatic actuation of the spindle of the lock.
2. Description of the Related Art
As door locks serve to protect the users"" safety and properties from burglars, the design of door locks is focused on easy operation and difficult accessibility to burglars. Conventional door locks are mostly operable mechanically by the use of keys, which is quite inconvenient. Therefore, electrically operated locks have been developed. However, most electrically operated locks cannot be opened once the power supply thereto is exhausted or interrupted.
Therefore, the main object of the present invention is to provide an electrically operated drive device adapted for driving a latch-actuating spindle of an electrically operable lock, which enables the lock to be actuated both manually and automatically.
Accordingly, an electrically operated drive device of this invention is adapted for driving a latch-actuating spindle of an electrically operable lock. The lock includes a deadbolt, a coupling member, a mounting frame, and a spindle. The deadbolt is adapted to be mounted in a door, and is movable between a retracted position and an extended position. The coupling member includes a connecting end connected to the deadbolt, and an actuated end disposed distal to the deadbolt. The mounting frame has a rear wall, and is adapted to be mounted on an interior of the door. The spindle defines an axis, and includes proximate and distal portions opposite to each other in an axial direction parallel to the axis, and an intermediate portion interposed between the proximate and distal portions. The intermediate portion is disposed such that the proximate portion is rotatably mounted in and extends outwardly and rearwardly of the rear wall to form a manually operated grip end, and such that the distal portion is turnable about the axis from a first position to a second position which is angularly spaced apart from the first position, thereby imparting a force to the actuated end of the coupling member to place the deadbolt in one of the retracted and extended positions. The electrically operated drive device includes a motor, a wheel gear, a drive transmitting member, a linearly shifting member, a crank member, a first cam mechanism, and a second cam mechanism. The motor has an output shaft and is adapted to be activated by an electric signal. The wheel gear has an inner annular surface defining a central hole, a toothed rim portion perimetrically opposite to the inner annular surface, and an annular major wall interposed between the inner annular surface and the toothed rim portion. The inner annular surface is adapted to be rotatably mounted on the intermediate portion and adjacent to the proximate portion. The drive transmitting member is disposed to transmit drive of the output shaft to the toothed rim portion so as to rotate the wheel gear. The shifting member includes first front and rear major walls opposite to each other, and is adapted to be loosely mounted on the intermediate portion so as to have the first rear major wall spaced apart from the annular major wall in the axial direction. The first front major wall defines a sliding slot which extends to be communicated with the first rear major wall. The sliding slot is elongated in a first direction transverse to the axial direction so as to define a transverse centerline that divides each of the first front and rear major walls into upper and lower halves, and a longitudinal centerline transverse to the transverse centerline so as to divide the sliding slot into right and left halves. The crank member includes a crankshaft adapted to be mounted coaxially on and to rotate with the intermediate portion, a crank web radially extending from the crankshaft and terminating at an anchoring end, and a crank pin extending from the anchoring end in the axial direction. The first cam mechanism includes a first cam member disposed on the annular major wall, and first upper and lower followers disposed respectively on the upper and lower halves of the first rear major wall of the shifting member. As such, when the first cam member rotates with the annular major wall to turn 180 degrees, the shifting member will move from one of rightmost and leftmost positions to the other one of the rightmost and leftmost positions in the first transverse direction. The second cam mechanism includes right and left translating cam surfaces and a second follower. The right and left translating cam surfaces are disposed on at least one of the upper and lower halves of the first front major wall of the shifting member, with a dead end juncture formed between the right and left translating cam surfaces. The dead end juncture cooperates with the right and left translating cam surfaces to establish a continuous sliding path such that the dead end juncture is moved from one of right and left positions to the other one of the right and left positions when the shifting member moves from a respective one of the rightmost and leftmost positions to the other one of the rightmost and leftmost positions. The second follower is disposed coaxially with the crank pin, and is retainingly slidable on the continuous sliding path such that when the second follower is brought to one of the right and left positions of the dead end juncture, the crankshaft will be turned to rotate with the intermediate portion of the spindle to a respective one of first and second positions.